THE CONCISE GUIDE TO PHARMACOLOGY 2017/18: Enzymes

Dual inhibition of cannabinoid CB1 receptor and inducible NOS attenuates obesity-induced chronic kidney disease

Background and Purpose

Obesity, an important risk factor for developing chronic kidney disease (CKD), affects the kidneys by two main molecular signalling pathways: the endocannabinoid/CB₁ receptor system, whose activation in obesity promotes renal inflammation, fibrosis, and injury, and the inducible NOS (iNOS), which generates ROS resulting in oxidative stress. Hence, a compound that inhibits both peripheral CB₁ receptors and iNOS may serve as an effective therapeutic agent against obesity‐induced CKD.

Experimental Approach

Here, we describe the effect of a novel peripherally restricted, orally bioavailable dual CB₁ receptor/iNOS antagonist, MRI‐1867 (3 mg·kg⁻¹), in ameliorating obesity‐induced CKD, and compared its metabolic and renal efficacies to a stand‐alone peripheral CB₁ receptor antagonist (JD5037; 3 mg·kg⁻¹), iNOS antagonist (1400W; 10 mg·kg⁻¹), and pair feeding. Mice with high‐fat diet‐induced obesity were treated orally with these compounds or vehicle (Veh) for 28 days. Standard diet‐fed mice treated with Veh served as controls.

Key Results

Enhanced expression of CB₁ receptors and iNOS in renal tubules was found in human kidney patients with obesity and other CKDs. The hybrid inhibitor ameliorated obesity‐induced kidney morphological and functional changes via decreasing kidney inflammation, fibrosis, oxidative stress, and renal injury. Some of these features were independent of the improved metabolic profile mediated via inhibition of CB₁ receptors. An additional interesting finding is that these beneficial effects on the kidney were partially associated with modulating renal adiponectin signalling.

Conclusions and Implications

Collectively, our results highlight the therapeutic relevance of blocking CB₁ receptors and iNOS in ameliorating obesity‐induced CKD.

Costunolide represses hepatic fibrosis through WW domain-containing protein 2-mediated Notch3 degradation

BACKGROUND AND PURPOSE

This study investigates the antifibrotic activities and potential mechanisms of costunolide (COS), a natural sesquiterpene compound.

EXPERIMENTAL APPROACH

Rats subjected to bile duct ligation and mice challenged with CCl₄ were used to study the antifibrotic effects of COS in vivo. Mouse primary hepatic stellate cells (pHSCs) and human HSC line LX-2 also served as an in vitro liver fibrosis models. The expression of fibrogenic genes and signaling proteins in the neurogenic locus notch homologue protein 3 (Notch3)-hairy/enhancer of split-1 (HES1) pathway was examined using western blot and/or real-time PCR. Notch3 degradation was analysed using immunofluorescence and coimmunoprecipitation.

KEY RESULTS

In animals, COS administration attenuated hepatic histopathological injury and collagen accumulation and reduced the expression of fibrogenic genes. COS time- and dose-dependently suppressed the levels of fibrotic markers in LX-2 cells and mouse pHSCs. Mechanistic studies showed COS destabilized Notch3 and subsequently inhibited the Notch3-HES1 pathway, thus inhibiting HSC activation. Furthermore, COS blocked the WW domain-containing protein 2 (WWP2)/protein phosphatase 1G (PPM1G) interaction and enhanced the effect of WWP2 on Notch3 degradation.

CONCLUSIONS AND IMPLICATIONS

COS exerted potent antifibrotic effects in vitro and in vivo by disrupting the WWP2/PPM1G complex, promoting Notch3 degradation and inhibiting the Notch3/HES1 pathway. This indicates that COS may be a potential therapeutic candidate for the treatment of liver fibrosis.

A bivalent antihypertensive vaccine targeting L-type calcium channels and angiotensin AT1 receptors

BACKGROUND AND PURPOSE

Hypertension has been the leading preventable cause of premature death worldwide. The aim of this study was to design a more efficient vaccine against novel targets for the treatment of hypertension.

EXPERIMENTAL APPROACH

The epitope CE12, derived from the human L-type calcium channel (Ca_V 1.2), was designed and conjugated with Qβ bacteriophage virus-like particles to test the efficacy in hypertensive animals. Further, the hepatitis B core antigen (HBcAg)-CE12-CQ10 vaccine, a bivalent vaccine based on HBcAg virus-like particles and targeting both human angiotensin AT₁ receptors and Ca_V 1.2 channels, was developed and evaluated in hypertensive rodents.

KEY RESULTS

The Qβ-CE12 vaccine effectively decreased the BP in hypertensive rodents. A monoclonal antibody against CE12 specifically bound to L-type calcium channels and inhibited channel activity. Injection with monoclonal antibody against CE12 effectively reduced the BP in angiotensin II-induced hypertensive mice. The HBcAg-CE12-CQ10 vaccine showed antihypertensive effects in hypertensive mice and relatively superior antihypertensive effects in spontaneously hypertensive rats and ameliorated L-NAME-induced renal injury. In addition, no obvious immune-mediated damage or electrophysiological adverse effects were detected.

CONCLUSION AND IMPLICATIONS

Immunotherapy against both AT₁ receptors and Ca_V 1.2 channels decreased the BP in hypertensive rodents effectively and provided protection against hypertensive target organ damage without obvious feedback activation of renin-angiotensin system or induction of dominant antibodies against the carrier protein. Thus, the HBcAg-CE12-CQ10 vaccine may provide a novel and promising therapeutic approach for hypertension.

Hesperidin supplementation has no effect on blood glucose control: A systematic review and meta-analysis of randomized controlled clinical trials

AIMS

To the best of our knowledge, no study has tried to quantitatively summarize the published evidence regarding the effect of hesperidin supplementation on blood glucose control. The present systematic review and meta-analysis of randomized controlled trials aimed to determine the effectiveness of hesperidin supplementation in improving blood glucose control in adults.

METHODS

Electronic databases including PubMed, ISI Web of Science, Scopus, and Google Scholar were searched up to February 2019. The risk of bias in individual studies was assessed using the Cochrane collaboration's tool. The overall estimates and their 95% confidence intervals (CIs) were calculated using a random-effects model.

RESULTS

Six trials with 318 participants were reviewed in the present systematic review. The results showed that hesperidin had no significant effect on serum fasting blood glucose (weighted mean difference [WMD] = -1.10 mg/dL, 95% CI: -3.79, 1.57), plasma insulin (WMD = -0.01 μU/mL, 95% CI: -1.20, 1.19), glycated haemoglobin A1c (WMD = -0.04%, 95% CI: -0.14, 0.04), homeostasis model assessment for insulin resistance (WMD = 0.117, 95% CI: -0.06, 0.29) and quantitative insulin sensitivity check index (WMD = 0.135; 95% CI: -0.13, 0.39), with no significant between-study heterogeneity. Subgroup analyses also indicated that the effects were not different based on the studies' design and duration, or the health status of the participants.

CONCLUSION

Although several animal studies have proposed that hesperidin supplementation might improve blood glucose control, the present study could not confirm this benefit in humans.

Binding site location on GABAA receptors determines whether mixtures of intravenous general anaesthetics interact synergistically or additively in vivo

BACKGROUND AND PURPOSE

General anaesthetics can act on synaptic GABA_A receptors by binding to one of three classes of general anaesthetic sites. Canonical drugs that bind selectively to only one class of site are etomidate, alphaxalone, and the mephobarbital derivative, R-mTFD-MPAB. We tested the hypothesis that the general anaesthetic potencies of mixtures of such site-selective agents binding to the same or to different sites would combine additively or synergistically respectively.

EXPERIMENTAL APPROACH

The potency of general anaesthetics individually or in combinations to cause loss of righting reflexes in tadpoles was determined, and the results were analysed using isobolographic methods.

KEY RESULTS

The potencies of combinations of two or three site-selective anaesthetics that all acted on a single class of site were strictly additive, regardless of which single site was involved. Combinations of two or three site-selective anaesthetics that all bound selectively to different sites always interacted synergistically. The strength of the synergy increased with the number of separate sites involved such that the percentage of each agent's EC₅₀ required to cause anaesthesia was just 35% and 14% for two or three sites respectively. Propofol, which binds non-selectively to the etomidate and R-mTFD-MPAB sites, interacted synergistically with each of these agents.

CONCLUSIONS AND IMPLICATIONS

The established pharmacology of the three anaesthetic binding sites on synaptic GABA_A receptors was sufficient to predict whether a mixture of anaesthetics interacted additively or synergistically to cause loss of righting reflexes in vivo. The principles established here have implications for clinical practice.

NO and hepatocellular cancer

NO has broad and sometimes dichotomous roles in cancer. The effects of NO in tumours depend on the type and localization of NOS isoforms, concentration and duration of NO exposure, and cellular sensitivity to NO. Hepatocellular carcinoma (HCC) is a common and lethal disease for which no effective therapy other than surgical resection exists. Over two decades of research has yielded evidence that NO generated by the inducible NOS (iNOS or NOS2) contributes to HCC progression in at least a subset of patients with HCC. The co-expression of iNOS with COX-2 may portend a particularly aggressive cancer phenotype in HCC and at the same time reveal an opportunity for pharmacological intervention. In this review, we focus on what is known about the influence of NO in HCC neoplastic transformation, proliferation and apoptosis, angiogenesis, invasion, and metastasis, cancer stem cells, and the host immune response against the tumour. We discuss the implications of recent findings for targeting the NO pathways in HCC.

Catalpol alleviates adriamycin-induced nephropathy by activating the SIRT1 signalling pathway in vivo and in vitro

BACKGROUND AND PURPOSE

Catalpol, a water-soluble active ingredient isolated from Rehmannia glutinosa, exhibits multiple pharmacological activities. However, the mechanism(s) underlying protection against renal injury by catalpol remains unknown.

EXPERIMENTAL APPROACH

Adriamycin-induced kidney injury models associated with podocyte damage were employed to investigate the nephroprotective effects of catalpol. In vivo, TUNEL and haematoxylin-eosin staining was used to evaluate the effect of catalpol on kidney injury in mice. In vitro, effects of catalpol on podocyte damage induced by adriamycin was determined by elisa kit, flow cytometry, Hoechst 33342, and TUNEL staining. The mechanism was investigated by siRNA, EX527, and docking simulations.

KEY RESULTS

In vivo, catalpol treatment significantly improved adriamycin-induced kidney pathological changes and decreased the number of apoptotic cells. In vitro, catalpol markedly decreased the intracellular accumulation of adriamycin and reduced the calcium ion level in podocytes and then attenuated apoptosis. Importantly, the regulatory effects of catalpol on sirtuin 1 (SIRT1), multidrug resistance-associated protein 2 (MRP2), and the TRPC6 channel were mostly abolished after incubation with SIRT1 siRNA or the SIRT1-specific inhibitor EX527. Furthermore, docking simulations showed that catalpol efficiently oriented itself in the active site of SIRT1, indicating a higher total binding affinity score than that of other SIRT1 activators, such as resveratrol, SRT2104, and quercetin.

CONCLUSION AND IMPLICATIONS

Taken together, our results suggest that catalpol exhibits strong protective effects against adriamycin-induced nephropathy by inducing SIRT1-mediated inhibition of TRPC6 expression and enhancing MRP2 expression.

Non-coding RNAs in bone remodelling and bone metastasis: Mechanisms of action and translational relevance

Bone metastases are frequent complications in patients with advanced cancer, which can be fatal or may rapidly impede the quality of life of patients. Current treatments for patients with bone metastases are palliative. Therefore, a better understanding of the molecular mechanisms that precede the overt development of skeletal lesions could lead to better therapeutic interventions. In this review, we present evidence that non-coding RNAs (ncRNAs) such as long ncRNAs, microRNAs, and circular RNAs are emerging as master regulators of bone metastasis formation. We highlight potential opportunities for the therapeutic targeting of ncRNAs. Furthermore, we discuss the possibility that ncRNAs may be used as biomarkers in the context of bone metastases, which might provide insight for improving the response to current bone-targeting therapies. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

Novel pharmacological actions of trequinsin hydrochloride improve human sperm cell motility and function

BACKGROUND AND PURPOSE

Asthenozoospermia is a leading cause of male infertility, but development of pharmacological agents to improve sperm motility is hindered by the lack of effective screening platforms and knowledge of suitable molecular targets. We have demonstrated that a high-throughput screening (HTS) strategy and established in vitro tests can identify and characterise compounds that improve sperm motility. Here, we applied HTS to identify new compounds from a novel small molecule library that increase intracellular calcium ([Ca²⁺ ]_i ), promote human sperm cell motility, and systematically determine the mechanism of action.

EXPERIMENTAL APPROACH

A validated HTS fluorometric [Ca²⁺ ]_i assay was used to screen an in-house library of compounds. Trequinsin hydrochloride (a PDE3 inhibitor) was selected for detailed molecular (plate reader assays, electrophysiology, and cyclic nucleotide measurement) and functional (motility and acrosome reaction) testing in sperm from healthy volunteer donors and, where possible, patients.

KEY RESULTS

Fluorometric assays identified trequinsin as an efficacious agonist of [Ca²⁺ ]_i , although less potent than progesterone. Functionally, trequinsin significantly increased cell hyperactivation and penetration into viscous medium in all donor sperm samples and cell hyperactivation in 22/25 (88%) patient sperm samples. Trequinsin-induced [Ca²⁺ ]_i responses were cross-desensitised consistently by PGE₁ but not progesterone. Whole-cell patch clamp electrophysiology confirmed that trequinsin activated CatSper and partly inhibited potassium channel activity. Trequinsin also increased intracellular cGMP.

CONCLUSION AND IMPLICATIONS

Trequinsin exhibits a novel pharmacological profile in human sperm and may be a suitable lead compound for the development of new agents to improve patient sperm function and fertilisation potential.

In vitro determination of the efficacy of illicit synthetic cannabinoids at CB1 receptors

BACKGROUND AND PURPOSE

The morbidity and mortality associated with recreational use of synthetic cannabinoid receptor agonists (SCRAs) may reflect strong activation of CB₁ receptors and is a major health concern. The properties of SCRA at CB₁ receptors are not well defined. Here we have developed an assay to determine acute CB₁ receptor efficacy using receptor depletion with the irreversible CB₁ receptor antagonist AM6544, with application of the Black and Leff operational model to calculate efficacy.

EXPERIMENTAL APPROACH

Receptor depletion in mouse AtT-20 pituitary adenoma cells stably expressing human CB₁ receptors was achieved by pretreatment of cells with AM6544 (10 μM, 60 min). The CB₁ receptor-mediated hyperpolarisation of AtT-20 cells was measured using fluorescence-based membrane potential dye. From data fit to the operational model, the efficacy (τ) and affinity (K_A ) parameters were obtained for each drug.

KEY RESULTS

AM6544 did not affect the potency or maximal effect of native somatostatin receptor-induced hyperpolarization. The τ value of ∆⁹ -THC was 80-fold less than the reference CB receptor agonist CP55940 and 260-fold less than the highest efficacy SCRA, 5F-MDMB-PICA. The operational efficacy of SCRAs ranged from 233 (5F-MDMB-PICA) to 28 (AB-PINACA), with CP55940 in the middle of the efficacy rank order. There was no correlation between the τ and K_A values.

CONCLUSIONS AND IMPLICATIONS

All SCRAs tested showed substantially higher efficacy at CB₁ receptors than ∆⁹ -THC, which may contribute to the adverse effects seen with these drugs but not ∆⁹ -THC.

Effects of the FGF receptor-1 inhibitor, infigratinib, with or without sildenafil, in experimental pulmonary arterial hypertension

BACKGROUND AND PURPOSE

Pulmonary arterial hypertension (PAH) is a progressive disease associated with high morbidity and mortality, despite advances in medical therapy. We compared the effects of infigratinib (NVP-BGJ398), a new FGF receptor-1 inhibitor, with or without the PDE-5 inhibitor sildenafil, on vascular function and remodelling as well as on gene expression of signal transducers for receptors of TGF-β (Smads-1/2/4) and transcription factor of endothelial-mesenchymal transition (Twist-1) in established experimental PAH. Types I and III pro-collagen and TGF-β expressions in lung fibroblasts were analysed in vitro after the different treatments.

EXPERIMENTAL APPROACH

PAH was induced in male Wistar rats with monocrotaline. 14 days later, treatments [sildenafil (SIL), infigratinib (INF) or their combination (SIL+INF)] were given for another 14 days. On Day 28, echocardiography and haemodynamic assays were performed, and lungs and pulmonary vessels were removed for analysis by histology, immunohistochemistry and RT-PCR. Fibroblasts prepared from PAH lungs were also analysed for TGF-β and pro-collagen.

KEY RESULTS

Only the combination of infigratinib and sildenafil significantly improved right ventricular systolic pressure and vascular remodelling parameters (right ventricular hypertrophy, smooth muscle α-actin, vessel wall thickness, and vascular collagen content). Infigratinib may act by reducing gene expression of Smads-1/4 and Twist-1 in lung tissue, as well as TGF-β and types I and III pro-collagen in lung fibroblasts.

CONCLUSIONS AND IMPLICATIONS

In this model of monocrotaline-induced PAH, the combination of the new inhibitor of FGF receptor-1, infigratinib, and sildenafil effectively improved haemodynamics and decreased vascular remodelling.

Andrographolide alleviates Parkinsonism in MPTP-PD mice via targeting mitochondrial fission mediated by dynamin-related protein 1

BACKGROUND AND PURPOSE

Accumulating evidence indicates that mitochondrial dynamics play an important role in the progressive deterioration of dopaminergic neurons. Andrographolide has been found to exert neuroprotective effects in several models of neurological diseases. However, the mechanism of how andrographolide protects neurons in Parkinson's disease (PD) remains not fully understood.

EXPERIMENTAL APPROACH

Behavioural experiments were performed to examine the effect of andrographolide in 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-PD mice. Mitochondrial mass and morphology were visualized using transmission electron microscopy (TEM). SH-SY5Y cells and primary mouse neurons were exposed to rotenone to mimic PD in vitro. Western blotting, co-immunoprecipitation and immunofluorescence were performed. The target protein of andrographolide was identified by biotin-andrographolide pulldown assay as well as drug affinity responsive target stability (DARTS), cellular thermal shift (CETSA), and surface plasmon resonance (SPR) assays.

KEY RESULTS

Andrographolide administration improved behavioural deficits and attenuated loss of dopaminergic neurons in MPTP-exposed mice and reduced cell death induced by rotenone in vitro. An increased mitochondrial mass, and decreased surface area were found in the striatum from MPTP-PD mice, as well as in rotenone-treated primary neurons and SH-SY5Y cells, while andrographolide treatment preserved mitochondrial mass and morphology. Dynamin-related protein 1 (DRP1) was identified as a target protein of andrographolide. Andrographolide bound to DRP1 and inhibited its GTPase activity, thereby preventing excessive mitochondria fission and neuronal damage in PD.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that andrographolide may protect neurons against rotenone- or MPTP-induced damage in vitro and in vivo through inhibiting mitochondrial fission.

Resveratrol suppresses the myofibroblastic phenotype and fibrosis formation in kidneys via proliferation-related signalling pathways

BACKGROUND AND PURPOSE

Renal fibrosis acts as the common pathway leading to the development of end-stage renal disease. Previous studies have shown that resveratrol has anti-fibrotic activity, but its potential molecular mechanisms of action are not well understood.

EXPERIMENTAL APPROACH

The anti-fibrotic effects of resveratrol were assayed in a rat model of unilateral ureteral obstruction (UUO) in vivo and in fibroblasts and tubular epithelial cells (TECs) stimulated by TGF-β1 in vitro. Gene and protein expression levels were analysed by PCR, Western blotting, and immunohistochemical staining.

KEY RESULTS

Resveratrol inhibits the myofibroblastic phenotype and fibrosis formation in UUO kidneys by targeting fibroblast-myofibroblast differentiation (FMD) and epithelial-mesenchymal transition (EMT). The anti-fibrotic effects of resveratrol correlated with decreased proliferation of TECs in the interstitium and tubules, resulting in suppressed activity of the proliferation-related signalling pathways, including that of the MAPK, PI3K/Akt, Wnt/β-catenin, and JAK2/STAT3 pathways. Resveratrol treatment suppressed TGF-β1-induced FMD and the expression of the myofibroblastic phenotype in fibroblasts in vitro by antagonizing the activation of proliferation-related signalling. Similarly, TGF-β1-mediated overactivation of the proliferation-related signalling in TECs induced EMT, and the myofibroblastic phenotype was suppressed by resveratrol. The anti-fibrotic and anti-proliferative effects of resveratrol were associated with the inactivation of Smad2/3 signalling and resulted in a partial reversal of FMD and EMT and the inhibition of the myofibroblastic phenotype.

CONCLUSIONS AND IMPLICATIONS

Resveratrol suppresses the myofibroblastic phenotype and fibrosis formation in vivo and in vitro via proliferation-related pathways, making it a potential therapeutic agent for preventing renal fibrosis.

New drugs approved for acute myeloid leukaemia in 2018

Acute myeloid leukaemia (AML) is a haematopoietic stem cell disorder, that is characterized by the clonal expansion of myeloid blasts and suppression of normal haematopoiesis. The 3 + 7 regimen is the backbone of standard first-line induction therapy among young/fit patients. However, in elderly and/or unfit patients with newly diagnosed AML, who cannot receive intensive chemotherapy, low-dose cytarabine or hypomethylating agents (azacitidine or decitabine) are the treatment options, which generally cannot induce durable responses. Among young/fit patients, for high-risk disease in first remission, or in cases with relapsed/refractory AML, allogeneic stem cell transplantation should be performed when complete remission is achieved. However, since AML is primarily a disease of the elderly, neither intensive chemotherapy nor allogeneic stem cell transplantation can be generally tolerated in most cases. There is clearly a need for new treatment options in elderly and young/unfit patients who cannot receive intensive chemotherapy. The discovery of novel molecular genetic markers (e.g. FMS-like tyrosine kinase 3, isocitrate dehydrogenase 1 and 2) resulted in the development of new therapeutic options in AML. This review mainly focuses on 4 targeted therapy agents; glasdegib and venetoclax used in combination treatment with low-dose cytarabine or hypomethylating agents among newly diagnosed cases with AML; and ivosidenib and gilteritinib as monotherapy in the treatment of relapsed/refractory AML, which were all approved by the US Food and Drug Administration in 2018.

Butyrate ameliorates caerulein-induced acute pancreatitis and associated intestinal injury by tissue-specific mechanisms

BACKGROUND AND PURPOSE

Acute pancreatitis (AP) is a common acute abdominal condition, frequently associated with intestinal barrier dysfunction, which aggravates AP retroactively. Butyrate exhibits anti-inflammatory effects in a variety of inflammatory diseases. However, its potential beneficial effect on AP and the underlying mechanisms have not been investigated.

EXPERIMENTAL APPROACH

Experimental AP was induced by caerulein hyperstimulation in wild-type and GPR109A-/- mice. Sodium butyrate was administered intragastrically for 7 days prior to caerulein hyperstimulation. Anti-inflammatory mechanisms of butyrate were further investigated in peritoneal macrophages.

KEY RESULTS

Butyrate prophylaxis attenuated AP as shown by reduced serum amylase and lipase levels, pancreatic oedema, myeloperoxidase activity, and improved pancreatic morphology. Amelioration of pancreatic damage by butyrate was associated with reduced levels of TNF-α, IL-6, and CCL2 and suppressed activation of the NLRP3 inflammasome in both pancreas and colon. Further, butyrate ameliorated pancreatic inflammation by suppressing interactions between histone deacetylase 1 (HDAC1) and AP1 and STAT1 with increased histone acetylation at H3K9, H3K14, H3K18, and H3K27 loci, resulting in suppression of NLRP3 inflammasome activation and modulation of immune cell infiltration in pancreas. Additionally, butyrate mediated STAT1/AP1-NLRP3 inflammasome suppression via HDAC1 inhibition was demonstrated in peritoneal macrophage. In colon, butyrate inhibited NLRP3 inflammasome activation via GPR109A. Accordingly, the modulatory effects of butyrate on AP, AP-associated gut dysfunction, and NLRP3 inflammasome activation were diminished in GPR109A-/- mice.

CONCLUSION AND IMPLICATIONS

Our study dissected tissue-specific anti-inflammatory mechanisms of butyrate during AP, suggesting that increased colonic levels of butyrate may be a strategy to protect against AP.

Modulation of the functions of myeloid-derived suppressor cells : a new strategy of hydrogen sulfide anti-cancer effects

BACKGROUND AND PURPOSE

Myeloid-derived suppressor cells (MDSCs) represent a major obstacle to cancer treatment, as they negatively regulate anti-tumour immunity through the suppression of tumour-specific T lymphocytes. Thus, the efficacy of immunotherapies may be improved by targeting MDSCs. In this study, we assessed the ability of hydrogen sulfide (H₂ S), a gasotransmitter whose anti-cancer effects are well known, to inhibit the accumulation and immunosuppressive functions of MDSCs in melanoma.

EXPERIMENTAL APPROACH

Effects of H₂ S on the host immune response to cancer were evaluated using an in vivo syngeneic model of murine melanoma. B16F10-melanoma-bearing mice were treated with the H₂ S donor, diallyl trisulfide (DATS) and analysed for content of MDSCs, dendritic cells (DCs) and T cells. Effects of H₂ S on expression of immunosuppressive genes in MDSCs and on T cell proliferation were evaluated.

KEY RESULTS

In melanoma-bearing mice, DATS inhibited tumour growth, and this effect was associated with a reduction in the frequency of MDSCs in the spleen, in the blood as well as in the tumour micro-environment. In addition, we found that CD8⁺ T cells and DCs were increased. Furthermore, DATS reduced the immuno-suppressive activity of MDSCs, restoring T cell proliferation.

CONCLUSIONS AND IMPLICATIONS

The H₂ S donor compound, DATS, inhibited the expansion and the suppressive functions of MDSCs, suggesting a novel role for H₂ S as a modulator of MDSCs in cancer. Therefore, H₂ S donors may provide a novel approach for enhancing the efficacy of melanoma immunotherapy.

LINKED ARTICLES

This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc.

Cannabichromene is a cannabinoid CB2 receptor agonist

BACKGROUND AND PURPOSE

Cannabichromene (CBC) is one of the most abundant phytocannabinoids in Cannabis spp. It has modest antinociceptive and anti-inflammatory effects and potentiates some effects of Δ⁹ -tetrahydrocannabinol in vivo. How CBC exerts these effects is poorly defined and there is little information about its efficacy at cannabinoid receptors. We sought to determine the functional activity of CBC at cannabinoid CB₁ and CB₂ receptors.

EXPERIMENTAL APPROACH

AtT20 cells stably expressing haemagglutinin-tagged human CB₁ and CB₂ receptors were used. Assays of cellular membrane potential and loss of cell surface receptors were performed.

KEY RESULTS

CBC activated CB₂ but not CB₁ receptors to produce hyperpolarization of AtT20 cells. This activation was inhibited by a CB₂ receptor antagonist AM630, and sensitive to Pertussis toxin. Application of CBC reduced activation of CB₂ , but not CB₁ , receptors by subsequent co-application of CP55,940, an efficacious CB₁ and CB₂ receptor agonist. Continuous CBC application induced loss of cell surface CB₂ receptors and desensitization of the CB₂ receptor-induced hyperpolarization.

CONCLUSIONS AND IMPLICATIONS

CBC is a selective CB₂ receptor agonist displaying higher efficacy than tetrahydrocannabinol in hyperpolarizing AtT20 cells. CBC can also recruit CB₂ receptor regulatory mechanisms. CBC may contribute to the potential therapeutic effectiveness of some cannabis preparations, potentially through CB₂ receptor-mediated modulation of inflammation.

LL1, a novel and highly selective STAT3 inhibitor, displays anti-colorectal cancer activities in vitro and in vivo

BACKGROUND AND PURPOSE

Signal transducer and activator of transcription 3 (STAT3) factor is associated with the development and progression of numerous types of human cancer. STAT3 activation is involved in metastasis. However, no STAT3 inhibitor has been used therapeutically. Hence, we syntheised a novel, potent and small-molecule inhibitor of STAT3, LL1, and studied its antitumour effects and investigated its mechanism of action in two tumour models.

EXPERIMENTAL APPROACH

Using structure-based drug design method, based on the crystal structure of STAT3 protein, we identified a potent STAT3 inhibitor (LL1) targeting STAT3 SH2 domain and characterized its therapeutic properties and potential toxicity in vitro and in vivo using the MTT assay, colony formation assay, histological, immunohistochemical, flow cytometric analysis, and tumour xenograft model.

KEY RESULTS

LL1 is highly selective among STATs family members and specifically inhibits phosphorylation of STAT3 Tyr-705 site, blocking the whole transmission process of STAT3 signalling. LL1 inhibited proliferation, colony formation, migration, and invasion of colonic cell lines. STAT3 is orally available to animals and suppresses tumour growth and metastasis in a dosage level compatible to clinical applications. Importantly, it does not cause significant toxicity at several times the effective dose.

CONCLUSIONS AND IMPLICATIONS

LL1 inhibits tumour growth and metastasis by blocking STAT3 signalling pathway. LL1 could be a promising therapeutic drug candidate for colorectal cancer by inhibiting the STAT3 activation.

Fenretinide treatment accelerates atherosclerosis development in apoE-deficient mice in spite of beneficial metabolic effects

BACKGROUND AND PURPOSE

Fenretinide, a synthetic retinoid derivative first investigated for cancer prevention and treatment, has been shown to ameliorate glucose tolerance, improve plasma lipid profile and reduce body fat mass. These effects, together with its ability to inhibit ceramide synthesis, suggest that fenretinide may have an anti-atherosclerotic action.

EXPERIMENTAL APPROACH

To this aim, nine-week-old apoE-knockout (EKO) female mice were fed for twelve weeks a Western diet, without (control) or with (0.1% w/w) fenretinide. As a reference, wild-type (WT) mice were treated similarly. Growth and metabolic parameters were monitored throughout the study. Atherosclerosis development was evaluated in the aorta and at the aortic sinus. Blood and lymphoid organs were further characterized with thorough cytological/histological and immunocytofluorimetric analyses.

KEY RESULTS

Fenretinide treatment significantly lowered body weight, glucose levels and plasma levels of total cholesterol, triglycerides, and phospholipids. In the liver, fenretinide remarkably reduced hepatic glycogenosis and steatosis driven by the Western diet. Treated spleens were abnormally enlarged, with severe follicular atrophy and massive extramedullary haematopoiesis. Severe renal hemosiderin deposition was observed in treated EKO mice. Treatment resulted in a threefold increase of total leukocytes (WT and EKO) and raised the activated/resting monocyte ratio in EKO mice. Finally, atherosclerosis development was markedly increased at the aortic arch, thoracic and abdominal aorta of fenretinide-treated mice.

CONCLUSIONS AND IMPLICATIONS

We provide the first evidence that, despite beneficial metabolic effects, fenretinide treatment may enhance the development of atherosclerosis.

Delayed intervention with a novel SGLT2 inhibitor NGI001 suppresses diet-induced metabolic dysfunction and non-alcoholic fatty liver disease in mice

BACKGROUND AND PURPOSE

Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic steatohepatitis, is closely related to metabolic diseases such as obesity and diabetes. Despite an accumulating number of studies, no pharmacotherapy that targets NAFLD has received general approval for clinical use.

EXPERIMENTAL APPROACH

Inhibition of the sodium-glucose cotransporter 2 (SGLT2) is a promising approach to treat diabetes, obesity, and associated metabolic disorders. In this study, we investigated the effect of a novel SGLT2 inhibitor, NGI001, on NAFLD and obesity-associated metabolic symptoms in high-fat diet (HFD)-induced obese mice.

KEY RESULTS

Delayed intervention with NGI001 protected against body weight gain, hyperglycaemia, hyperlipidaemia, and hyperinsulinaemia, compared with HFD alone. Adipocyte hypertrophy was prevented by administering NGI001. NGI001 inhibited impaired glucose metabolism and regulated the secretion of adipokines associated with insulin resistance. In addition, NGI001 supplementation suppressed hepatic lipid accumulation and inflammation but had little effect on kidney function. In-depth investigations showed that NGI001 ameliorated fat deposition and increased AMPK phosphorylation, resulting in phosphorylation of its major downstream target, acetyl-CoA carboxylase, in human hepatocyte HuS-E/2 cells. This cascade ultimately led to the down-regulation of downstream fatty acid synthesis-related molecules and the up-regulation of downstream β oxidation-associated molecules. Surprisingly, NGI001 decreased gene and protein expression of SGLT1 and SGLT2 and glucose uptake in oleic acid-treated HuS-E/2 cells.

CONCLUSION AND IMPLICATIONS

Our findings suggest the novel SGLT2 inhibitor, NGI001 has therapeutic potential to attenuate or delay the onset of diet-induced metabolic diseases and NAFLD.

Isoniazid and host immune system interactions: A proposal for a novel comprehensive mode of action

The known mode of action of isoniazid (INH) is to inhibit bacterial cell wall synthesis following activation by the bacterial catalase-peroxidase enzyme KatG in Mycobacterium tuberculosis (Mtb). This simplistic model fails to explain (a) how isoniazid penetrates waxy granulomas with its very low lipophilicity, (b) how isoniazid kills latent Mtb lacking a typical cell wall, and (c) why isoniazid treatment time is remarkably long in contrast to most other antibiotics. To address these questions, a novel comprehensive mode of action of isoniazid has been proposed here. Briefly, isoniazid eradicates latent tuberculosis (TB) by prompting slow differentiation of pro-inflammatory monocytes and providing protection against reactive species-induced "self-necrosis" of phagocytes. In the case of active TB, different immune cells form INH-NAD⁺ adducts to inhibit Mtb's cell wall biosynthesis. This additionally suggests that the antibacterial properties of INH do not rely on KatG of Mtb. As such, isoniazid-resistant TB needs to be re-evaluated.

The effects of di(2-ethylhexyl) phthalate exposure in women with polycystic ovary syndrome undergoing in vitro fertilization

Objectives

Di(2-ethylhexyl) phthalate (DEHP) is a common endocrine-disrupting chemical, which has potential reproductive toxicity. This study aimed to explore the effects of DEHP exposure in women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization.

Methods

In this case-control study, DEHP levels in follicular fluid (FF) of women with PCOS (n = 56) and controls (n = 51) were measured. The in vitro effects of DEHP exposure on primary-cultured human granulosa cells (GCs) and a steroidogenic human granulosa-like tumor cell line (KGN cells) were analyzed.

Results

Concentrations of DEHP in FF were significantly higher in women with PCOS than in controls. The clinical pregnancy rate was significantly lower in women with PCOS with high levels of DEHP than in controls. The levels of androgens produced by human GCs were significantly increased following DEHP exposure. Compared with controls, DEHP-treated human GCs and KGN cells showed significantly lower viability, cell cycle arrest, higher apoptosis, and altered expression of apoptosis-related genes.

Conclusion

Women with PCOS are exposed to increased levels of DEHP in follicles, which may be associated with pregnancy loss following in vitro fertilization. DEHP may disrupt steroid production, balance in cellular proliferation, and apoptosis in human granulosa cells.

Stress granule: A promising target for cancer treatment

Stress granules (SGs) are primarily composed of mRNAs that stall at translation initiation and usually appear in the cytoplasm under unusual physiological or pathological conditions such as hypoxia, oxidative stress, and viral infection. Recent studies have indicated that several components of SGs participate in tumourigenesis and cancer metastasis through tumour-associated signalling pathways as well as other mechanisms. Furthermore, some chemotherapy drugs have been reported to induce SGs. Thus, the roles of SGs in cancer treatment have attracted considerable interest. Importantly, disturbing the recruitment of SGs components or microtubule polymerization, as well as other strategies that can abolish SGs formation, is reported to inhibit tumour progression, suggesting that targeting SGs could be a promising strategy for cancer treatment. In this review, we summarize the relationship between SGs and cancer, as well as recent advances in targeting SGs, in the interest of providing new opportunities for cancer treatment.

Targeting the peptidase PCSK9 to reduce cardiovascular risk: Implications for basic science and upcoming challenges

LDL cholesterol (LDL-C) plays a central role in the progression of atherosclerosis. Statin therapy for lowering LDL-C reduces the risk of atherosclerotic cardiovascular disease and is the recommended first-line treatment for patients with high LDL-C levels. However, some patients are unable to achieve an adequate reduction in LDL-C with statins or are statin-intolerant; thus, PCSK9 inhibitors were developed to reduce LDL-C levels, instead of statin therapy. PCSK9 monoclonal antibodies dramatically reduce LDL-C levels and cardiovascular risk, and promising new PCSK9 inhibitors using different mechanisms are currently being developed. The absolute benefit of LDL-C reduction depends on the individual absolute risk and the achieved absolute reduction in LDL-C. Therefore, PCSK9 inhibitors may provide the greatest benefits from further LDL-C reduction for the highest risk patients. Here, we focus on PCSK9-targeted therapies and discuss the challenges of LDL-C reduction for prevention of atherosclerotic cardiovascular disease.

CR4056, a powerful analgesic imidazoline-2 receptor ligand, inhibits the inflammation-induced PKCε phosphorylation and membrane translocation in sensory neurons

BACKGROUND AND PURPOSE

CR4056 is a first-in-class imidazoline-2 (I₂ ) receptor ligand characterized by potent analgesic activity in different experimental animal models of pain. In a recent phase II clinical trial, CR4056 effectively reduced pain in patients with knee osteoarthritis. In the present study, we investigated the effects of CR4056 on PKCε translocation in vitro and on PKCε activation in vivo in dorsal root ganglia (DRG) neurons.

EXPERIMENTAL APPROACH

Effects of CR4056 on bradykinin-induced PKCε translocation were studied in rat sensory neurons by immunocytochemistry. PKCε activation was investigated by immunohistochemistry analysis of DRG from complete Freund's adjuvant-treated animals developing local hyperalgesia. The analgesic activity of CR4056 was tested on the same animals.

KEY RESULTS

CR4056 inhibited PKCε translocation with very rapid and long-lasting activity. CR4056 decreased hyperalgesia and phospho-PKCε immunoreactivity in the DRG neurons innervating the inflamed paw. The effect of CR4056 on PKCε translocation was blocked by pertussis toxin, implying that the intracellular pathways involved G_i proteins. The inhibition of PKCε translocation by CR4056 was independent of the α₂ -adrenoeceptor and, surprisingly, was also independent of idazoxan-sensitive I₂ binding sites. The I₂ agonist 2BFI had no effect alone but potentiated the activity of low concentrations of CR4056.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrate that CR4056 shares the ability to inhibit PKCε translocation with other analgesics. Whether the inhibition of PKCε involves binding to specific subtype(s) of I₂ receptors should be further investigated. If so, this would be a new mode of action of a highly specific I₂ receptor ligand.

Functional contribution of sphingosine-1-phosphate to airway pathology in cigarette smoke-exposed mice

BACKGROUND AND PURPOSE

A critical role for sphingosine kinase/sphingosine-1-phosphate (S1P) pathway in the control of airway function has been demonstrated in respiratory diseases. Here, we address S1P contribution in a mouse model of mild chronic obstructive pulmonary disease (COPD).

EXPERIMENTAL APPROACH

C57BL/6J mice have been exposed to room air or cigarette smoke up to 11 months and killed at different time points. Functional and molecular studies have been performed.

KEY RESULTS

Cigarette smoke caused emphysematous changes throughout the lung parenchyma coupled to a progressive collagen deposition in both peribronchiolar and peribronchial areas. The high and low airways showed an increased reactivity to cholinergic stimulation and α-smooth muscle actin overexpression. Similarly, an increase in airway reactivity and lung resistances following S1P challenge occurred in smoking mice. A high expression of S1P, Sph-K₂ , and S1P receptors (S1P₂ and S1P₃ ) has been detected in the lung of smoking mice. Sphingosine kinases inhibition reversed the increased cholinergic response in airways of smoking mice.

CONCLUSIONS AND IMPLICATIONS

S1P signalling up-regulation follows the disease progression in smoking mice and is involved in the development of airway hyperresponsiveness. Our study defines a therapeutic potential for S1P inhibitors in management of airways hyperresponsiveness associated to emphysema in smokers with both asthma and COPD.

Characterisation of nerve-mediated ATP release from bladder detrusor muscle and its pathological implications

BACKGROUND AND PURPOSE

This study aims to characterise the molecular mechanisms that determine variability of atropine resistance of nerve-mediated contractions in human and guinea pig detrusor smooth muscle.

EXPERIMENTAL APPROACH

Atropine resistance of nerve-mediated contractions and the role of P2X1 receptors, were assessed in isolated preparations from guinea pigs and also humans with or without overactive bladder syndrome, from which the mucosa was removed. Nerve-mediated ATP release was measured directly with amperometric ATP-sensitive electrodes. Ecto-ATPase activity of guinea pig and human detrusor samples was measured in vitro by measuring the concentration-dependent rate of ATP breakdown. The transcription of ecto-ATPase subtypes in human samples was measured by qPCR.

KEY RESULTS

Atropine resistance was greatest in guinea pig detrusor, absent in human tissue from normally functioning bladders, and intermediate in human overactive bladder. Greater atropine resistance correlated with reduction of contractions by the ATP-diphosphohydrolase apyrase, directly implicating ATP in their generation. E-NTPDase-1 was the most abundantly transcribed ecto-ATPase of those tested, and transcription was reduced in tissue from human overactive, compared to normal, bladders. E-NTPDase-1 enzymic activity was inversely related to the magnitude of atropine resistance. Nerve-mediated ATP release was continually measured and varied with stimulation frequency over the range of 1-16 Hz.

CONCLUSION AND IMPLICATIONS

Atropine resistance in nerve-mediated detrusor contractions is due to ATP release and its magnitude is inversely related to E-NTPDase-1 activity. ATP is released under different stimulation conditions compared with ACh, implying different routes for their release.

The role of chemokines and chemokine receptors in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by progressive pulmonary artery remodelling leading to increased right ventricular pressure overload, which results in right heart failure and premature death. Inflammation plays a central role in the development of PAH, and the recruitment and function of immune cells are tightly regulated by chemotactic cytokines called chemokines. A number of studies have shown that the development and progression of PAH are associated with the dysregulated expression of several chemokines and chemokine receptors in the pulmonary vasculature. Moreover, some chemokines are differentially regulated in the pressure-overloaded right ventricle. Recent studies have tested the efficacy of pharmacological agents targeting several chemokines and chemokine receptors for their effects on the development of PAH, suggesting that these receptors could serve as useful therapeutic targets. In this review, we provide recent insights into the role of chemokines and chemokine receptors in PAH and RV remodelling and the opportunities and roadblocks in targeting them. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc.

Mechanisms underlying the inhibitory effects of probucol on elastase-induced abdominal aortic aneurysm in mice

BACKGROUND AND PURPOSE

Abdominal aortic aneurysm (AAA) is a degenerative disease with irreversible and progressive dilation of the artery. But there are few options for efficacious treatment except for traditional surgery. Probucol has been widely applied to treat hyperlipidaemia and atherosclerosis in clinic, but whether it can protect against AAA remains unknown. In this study, the protective effects of probucol against AAA and its related mechanisms were explored.

EXPERIMENTAL APPROACH

The model of AAA was induced in mice by periaortic application of elastase (40 min) to the abdominal aorta. Probucol at different doses was administered by daily gavage, starting on the same day as AAA was induced, for 14 days. In vitro, cultures of rat vascular smooth muscle cells (VSMCs) were stimulated with TNF-α. Haem oxygenase (HO)-1 siRNA and HO-1 plasmid were used to regulate the expression or activity of HO-1 in the VSMCs and to clarify the effects of HO-1.

KEY RESULTS

Probucol dose-dependently prevented the development of AAA, reflected by decreased incidence of AAA, diameter of aortic dilation, elastin degradation, and infiltration of inflammatory cells. Probucol also protected VSMCs from oxidative injury and enhanced elastin biosynthesis. This anti-inflammatory effects of probucol on VSMCs were significantly decreased when HO-1 was inhibited by siRNA.

CONCLUSION AND IMPLICATIONS

Probucol protected against AAA through inhibiting the degradation of elastin induced by inflammation and oxidation and by facilitating the biosynthesis of elastin. HO-1 played a crucial role in the anti-inflammatory effects of probucol in VSMCs.

Programmed necrosis in cardiomyocytes: mitochondria, death receptors and beyond

Excessive death of cardiac myocytes leads to many cardiac diseases, including myocardial infarction, arrhythmia, heart failure and sudden cardiac death. For the last several decades, most work on cell death has focused on apoptosis, which is generally considered as the only form of regulated cell death, whereas necrosis has been regarded to be an unregulated process. Recent findings reveal that necrosis also occurs in a regulated manner and that it is closely related to the physiology and pathophysiology of many organs, including the heart. The recognition of necrosis as a regulated process mandates a re-examination of cell death in the heart together with the mechanisms and therapy of cardiac diseases. In this study, we summarize the regulatory mechanisms of the programmed necrosis of cardiomyocytes, that is, the intrinsic (mitochondrial) and extrinsic (death receptor) pathways. Furthermore, the role of this programmed necrosis in various heart diseases is also delineated. Finally, we describe the currently known pharmacological inhibitors of several of the key regulatory molecules of regulated cell necrosis and the opportunities for their therapeutic use in cardiac disease. We intend to systemically summarize the recent progresses in the regulation and pathological significance of programmed cardiomyocyte necrosis along with its potential therapeutic applications to cardiac diseases. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Mitochondrial function in the heart: the insight into mechanisms and therapeutic potentials

Mitochondrial dysfunction is considered as a crucial contributory factor in cardiac pathology. This has highlighted the therapeutic potential of targeting mitochondria to prevent or treat cardiac disease. Mitochondrial dysfunction is associated with aberrant electron transport chain activity, reduced ATP production, an abnormal shift in metabolic substrates, ROS overproduction and impaired mitochondrial dynamics. This review will cover the mitochondrial functions and how they are altered in various disease conditions. Furthermore, the mechanisms that lead to mitochondrial defects and the protective mechanisms that prevent mitochondrial damage will be discussed. Finally, potential mitochondrial targets for novel therapeutic intervention will be explored. We will highlight the development of small molecules that target mitochondria from different perspectives and their current progress in clinical trials. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Exploring mitochondrial cholesterol signalling for therapeutic intervention in neurological conditions

The pharmacological targeting of cholesterol levels continues to generate interest due to the undoubted success of therapeutic agents, such as statins, in extending life expectancy by modifying the prognosis of diseases associated with the impairment of lipid metabolism. Advances in our understanding of mitochondrial dysfunction in chronic age-related diseases of the brain have disclosed an emerging role for mitochondrial cholesterol in their pathophysiology, thus delineating an opportunity to provide mechanistic insights and explore strategies of intervention. This review draws attention to novel signalling mechanisms in conditions linked with impaired metabolism associated with impaired handling of cholesterol and its oxidized forms (oxysterols) by mitochondria. By emphasizing the role of mitochondrial cholesterol in neurological diseases, we here call for novel approaches and new means of assessment. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Inhibiting nucleolin reduces inflammation induced by mitochondrial DNA in cardiomyocytes exposed to hypoxia and reoxygenation

BACKGROUND AND PURPOSE

Cellular debris causes sterile inflammation after myocardial infarction. Mitochondria constitute about 30 percent of the human heart. Mitochondrial DNA (mtDNA) is a damage-associated-molecular-pattern that induce injurious sterile inflammation. Little is known about mtDNA's inflammatory signalling pathways in cardiomyocytes and how mtDNA is internalized to associate with its putative receptor, toll-like receptor 9 (TLR9).

EXPERIMENTAL APPROACH

We hypothesized that mtDNA can be internalized in cardiomyocytes and induce an inflammatory response. Adult mouse cardiomyocytes were exposed to hypoxia-reoxygenation and extracellular DNA. Microscale thermophoresis was used to demonstrate binding between nucleolin and DNA.

KEY RESULTS

Expression of the pro-inflammatory cytokines IL-1β and TNFα were upregulated by mtDNA, but not by nuclear DNA (nDNA), in cardiomyocytes exposed to hypoxia-reoxygenation. Blocking the RNA/DNA binding protein nucleolin with midkine reduced expression of IL-1β/TNFα and the nucleolin inhibitor AS1411 reduced interleukin-6 release in adult mouse cardiomyocytes. mtDNA bound 10-fold stronger than nDNA to nucleolin. In HEK293-NF-κB reporter cells, mtDNA induced NF-κB activity in normoxia, while CpG-DNA and hypoxia-reoxygenation, synergistically induced TLR9-dependent NF-κB activity. Protein expression of nucleolin was found in the plasma membrane of cardiomyocytes and inhibition of nucleolin with midkine inhibited cellular uptake of CpG-DNA. Inhibition of endocytosis did not reduce CpG-DNA uptake in cardiomyocytes.

CONCLUSION AND IMPLICATIONS

mtDNA, but not nDNA, induce an inflammatory response in mouse cardiomyocytes during hypoxia-reoxygenation. In cardiomyocytes, nucleolin is expressed on the membrane and blocking nucleolin reduce inflammation. Nucleolin might be a therapeutic target to prevent uptake of immunogenic DNA and reduce inflammation.

LINKED ARTICLES

This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Sex differences in schizophrenia, bipolar disorder, and post-traumatic stress disorder: Are gonadal hormones the link?

In this review, we describe the sex differences in prevalence, onset, symptom profiles, and disease outcome that are evident in schizophrenia, bipolar disorder, and post-traumatic stress disorder. Women with schizophrenia tend to exhibit less disease impairment than men. By contrast, women with post-traumatic stress disorder are more affected than men. The most likely candidates to explain these sex differences are gonadal hormones. This review details the clinical evidence that oestradiol and progesterone are dysregulated in these psychiatric disorders. Notably, existing data on oestradiol, and to a lesser extent, progesterone, suggest that low levels of these hormones may increase the risk of disease development and worsen symptom severity. We argue that future studies require a more inclusive, considered analysis of gonadal steroid hormones and the intricacies of the interactions between them, with methodological rigour applied, to enhance our understanding of the roles of steroid hormones in psychiatric disorders. LINKED ARTICLES: This article is part of a themed section on The Importance of Sex Differences in Pharmacology Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.21/issuetoc.

OSCP subunit of mitochondrial ATP synthase: role in regulation of enzyme function and of its transition to a pore

The permeability transition pore (PTP) is a latent, high-conductance channel of the inner mitochondrial membrane. When activated, it plays a key role in cell death and therefore in several diseases. The investigation of the PTP took an unexpected turn after the discovery that cyclophilin D (the target of the PTP inhibitory effect of cyclosporin A) binds to FO F1 (F)-ATP synthase, thus inhibiting its catalytic activity by about 30%. This observation was followed by the demonstration that binding occurs at a particular subunit of the enzyme, the oligomycin sensitivity conferral protein (OSCP), and that F-ATP synthase can form Ca2+ -activated, high-conductance channels with features matching those of the PTP, suggesting that the latter originates from a conformational change in F-ATP synthase. This review is specifically focused on the OSCP subunit of F-ATP synthase, whose unique features make it a potential pharmacological target both for modulation of F-ATP synthase and its transition to a pore. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

A phase I pharmacokinetic study of belinostat in patients with advanced cancers and varying degrees of liver dysfunction

AIMS

The histone deacetylase inhibitor belinostat has activity in various cancers. Because belinostat is metabolized by the liver, reduced hepatic clearance could lead to excessive drug accumulation and increased toxicity. Safety data in patients with liver dysfunction are needed for this drug to reach its full potential in the clinic.

METHODS

We performed a phase 1 trial to determine the safety, maximum tolerated dose (MTD) and pharmacokinetics of belinostat in patients with advanced cancer and varying degrees of liver dysfunction.

RESULTS

Seventy-two patients were enrolled and divided into cohorts based on liver function. In patients with mild dysfunction, the MTD was the same as the recommended phase 2 dose (1000 mg/m2 /day). Belinostat was well tolerated in patients with moderate and severe liver dysfunction, although the trial was closed before the MTD in these cohorts could be determined. The mean clearance of belinostat was 661 mL/min/m2 in patients with normal liver function, compared to 542, 505 and 444 mL/min/m2 in patients with mild, moderate and severe hepatic dysfunction. Although this trial was not designed to assess clinical activity, of the 47 patients evaluable for response, 13 patients (28%) experienced stable disease.

CONCLUSION

While a statistically significant difference in clearance indicates increased belinostat exposure with worsening liver function, no relationship was observed between belinostat exposure and toxicity. An assessment of belinostat metabolites revealed significant differences in metabolic pathway capability in patients with differing levels of liver dysfunction. Further studies are needed to establish formal dosing guidelines in this patient population.

The roles of gut microbiota and circadian rhythm in the cardiovascular protective effects of polyphenols

Polyphenols are secondary metabolites of plants that have been widely studied for their health benefits as antioxidants. In the last decade, several clinical trials and epidemiological studies have shown that long‐term consumption of polyphenol‐rich diet protects against chronic diseases such as cancers and cardiovascular diseases. Current cardiovascular studies have also suggested an important role of gut microbiota and circadian rhythm in the pathogenesis metabolic and cardiovascular diseases. It is known that polyphenols can modulate the composition of core gut microbiota and interact with circadian clocks. In this article, we summarize recent findings, review the molecular mechanisms and the potential of polyphenols as dietary supplements for regulating gut microbiota and circadian rhythms, and discuss future research directions.

Linked Articles

This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc

Relaxin reduces endothelium-derived vasoconstriction in hypertension: Revealing new therapeutic insights

BACKGROUND AND PURPOSE

Endothelium-derived vasoconstriction is a hallmark of vascular dysfunction in hypertension. In some cases, an overproduction of endothelium-derived prostacyclin (PGI₂ ) can cause contraction rather than relaxation. Relaxin is well known for its vasoprotective actions, but the possibility that this peptide could also reverse endothelium-derived vasoconstriction has never been investigated. We tested the hypothesis that short-term relaxin treatment mitigates endothelium-derived vasoconstriction in spontaneously hypertensive rats (SHR).

EXPERIMENTAL APPROACH

Male Wistar Kyoto rats (WKY) and SHR were subcutaneously infused with either vehicle (20 mmol·L^-1 sodium acetate) or relaxin (13.3 μg·kg^-1 ·hr^-1 ) using osmotic minipumps for 3 days. Vascular reactivity to the endothelium-dependent agonist ACh was assessed in vitro by wire myography. Quantitative PCR and LC-MS were used to identify changes in gene expression of prostanoid pathways and PG production, respectively.

KEY RESULTS

Relaxin treatment ameliorated hypertension-induced endothelial dysfunction by increasing NO-dependent relaxation and reducing endothelium-dependent contraction. Notably, short-term relaxin treatment up-regulated mesenteric PGI₂ receptor (IP) expression, permitting PGI₂ -IP-mediated vasorelaxation. In the aorta, reversal of contraction was accompanied by suppression of the hypertension-induced increase in prostanoid-producing enzymes and reduction in PGI₂ -evoked contractions.

CONCLUSIONS AND IMPLICATIONS

Relaxin has region-dependent vasoprotective actions in hypertension. Specifically, relaxin has distinct effects on endothelium-derived contracting factors and their associated vasoconstrictor pathways in mesenteric arteries and the aorta. Taken together, these observations reveal the potential of relaxin as a new therapeutic agent for vascular disorders that are associated with endothelium-derived vasoconstriction including hypertension.

Trichostatin A blocks aldosterone-induced Na+ transport and control of serum- and glucocorticoid-inducible kinase 1 in cortical collecting duct cells

BACKGROUND AND PURPOSE

Aldosterone stimulates epithelial Na⁺ channel (ENaC)-dependent Na⁺ retention in the cortical collecting duct (CCD) of the kidney by activating mineralocorticoid receptors that promote expression of serum and glucocorticoid-inducible kinase 1 (SGK1). This response is critical to BP homeostasis. It has previously been suggested that inhibiting lysine deacetylases (KDACs) can post-transcriptionally disrupt this response by promoting acetylation of the mineralocorticoid receptor. The present study critically evaluates this hypothesis.

EXPERIMENTAL APPROACH

Electrometric and molecular methods were used to define the effects of a pan-KDAC inhibitor, trichostatin A, on the responses to a physiologically relevant concentration of aldosterone (3 nM) in murine mCCD_cl1 cells.

KEY RESULTS

Aldosterone augmented ENaC-induced Na⁺ absorption and increased SGK1 activity and abundance, as expected. In the presence of trichostatin A, these responses were suppressed. Trichostatin A-induced inhibition of KDAC was confirmed by increased acetylation of histone H3, H4, and α-tubulin. Trichostatin A did not block the electrometric response to insulin, a hormone that activates SGK1 independently of increased transcription, indicating that trichostatin A has no direct effect upon the SGK1/ENaC pathway.

CONCLUSIONS AND IMPLICATIONS

Inhibition of lysine de-acetylation suppresses aldosterone-dependent control over the SGK1-ENaC pathway but does not perturb post-transcriptional signalling, providing a physiological basis for the anti-hypertensive action of KDAC inhibition seen in vivo.

Myricanol modulates skeletal muscle-adipose tissue crosstalk to alleviate high-fat diet-induced obesity and insulin resistance

BACKGROUND AND PURPOSE

Skeletal muscle is the predominant site for glucose disposal and fatty acid consumption. Emerging evidence indicates that the crosstalk between adipose tissue and skeletal muscle is critical in maintaining insulin sensitivity and lipid homeostasis. The current study was designed to investigate whether myricanol improves insulin sensitivity and alleviates adiposity through modulating skeletal muscle-adipose tissue crosstalk.

EXPERIMENTAL APPROACH

The therapeutic effect of myricanol was evaluated on palmitic acid (PA)-treated C2C12 myotubes and high-fat diet (HFD)-fed mice. The crosstalk between myotubes and adipocytes was evaluated using Transwell assay. The cellular lipid content was examined by Nile red staining. The mitochondrial content was assessed by MitoTracker Green staining and citrate synthase activity, and the mitochondrial function was examined by Seahorse assay. Expression of mitochondria-related and insulin signalling pathway proteins was analysed by Western blot, and the irisin level was determined by elisa kit.

KEY RESULTS

Myricanol increased mitochondrial quantity and function through activating AMP-activated protein kinase, resulting in reduced lipid accumulation and enhanced insulin-stimulated glucose uptake, in PA-treated C2C12 myotubes. Furthermore, myricanol stimulated irisin production and secretion from myotubes to reduce lipid content in 3T3-L1 adipocytes. In HFD-fed mice, myricanol treatment alleviated adiposity and insulin resistance through enhancing lipid utilization and irisin production in skeletal muscle and inducing browning of inguinal fat.

CONCLUSIONS AND IMPLICATIONS

Myricanol modulates skeletal muscle-adipose tissue crosstalk, to stimulate browning of adipose tissue and improve insulin sensitivity in skeletal muscle. Myricanol might be a potential candidate for treating insulin resistance and obesity.

The effect of two selective A1 -receptor agonists and the bitopic ligand VCP746 on heart rate and regional vascular conductance in conscious rats

Background and Purpose

Adenosine is a local mediator that regulates physiological and pathological processes via activation of four GPCRs (A₁, A_2A, A_2B, and A₃). We have investigated the effect of two A₁‐receptor‐selective agonists and the novel A₁‐receptor bitopic ligand VCP746 on the rat cardiovascular system.

Experimental Approach

The regional haemodynamic responses of these agonist was investigated in conscious rats. Male Sprague–Dawley rats (350–450 g) were chronically implanted with pulsed Doppler flow probes on the renal, mesenteric arteries and the descending abdominal aorta and the jugular vein and caudal artery catheterized. Cardiovascular responses were measured following intravenous infusion (3 min each dose) of CCPA (120, 400, and 1,200 ng·kg⁻¹·min⁻¹), capadenoson or adenosine (30, 100, and 300 μg·kg⁻¹·min⁻¹), or VCP746 (6, 20, and 60 μg·kg⁻¹·min⁻¹) following pre‐dosing with DPCPX (0.1 mg·kg⁻¹, i.v.) or vehicle.

Key Results

CCPA produced a significant A₁‐receptor‐mediated decrease in heart rate that was accompanied by vasoconstrictions in the renal and mesenteric vascular beds but an increase in hindquarters vascular conductance. The partial agonist capadenoson also produced an A₁‐receptor‐mediated bradycardia. In contrast, VCP746 produced increases in heart rate and renal and mesenteric vascular conductance that were not mediated by A₁‐receptors. In vitro studies confirmed that VCP746 had potent agonist activity at both A_2A‐ and A_2B‐receptors.

Conclusions and Implications

These results suggest VCP746 mediates its cardiovascular effects via activation of A₂ rather than A₁ adenosine receptors. This has implications for the design of future bitopic ligands that incorporate A₁ allosteric ligand moieties.

The role of smooth muscle cells in plaque stability: Therapeutic targeting potential

Events responsible for cardiovascular mortality and morbidity are predominantly caused by rupture of "vulnerable" atherosclerotic lesions. Vascular smooth muscle cells (VSMCs) play a key role in atherogenesis and have historically been considered beneficial for plaque stability. VSMCs constitute the main cellular component of the protective fibrous cap within lesions and are responsible for synthesising strength-giving extracellular matrix components. However, lineage-tracing experiments in mouse models of atherosclerosis have shown that, in addition to the fibrous cap, VSMCs also give rise to many of the cell types found within the plaque core. In particular, VSMCs generate a substantial fraction of lipid-laden foam cells, and VSMC-derived cells expressing markers of macrophages, osteochondrocyte, and mesenchymal stem cells have been observed within lesions. Here, we review recent studies that have changed our perspective on VSMC function in atherosclerosis and discuss how VSMCs could be targeted to increase plaque stability.

Pharmacological inhibition of Hippo pathway, with the novel kinase inhibitor XMU-MP-1, protects the heart against adverse effects during pressure overload

BACKGROUND AND PURPOSE

The Hippo pathway has emerged as a potential therapeutic target to control pathological cardiac remodelling. The core components of the Hippo pathway, mammalian Ste-20 like kinase 1 (Mst1) and mammalian Ste-20 like kinase 2 (Mst2), modulate cardiac hypertrophy, apoptosis, and fibrosis. Here, we study the effects of pharmacological inhibition of Mst1/2 using a novel inhibitor XMU-MP-1 in controlling the adverse effects of pressure overload-induced hypertrophy.

EXPERIMENTAL APPROACH

We used cultured neonatal rat cardiomyocytes (NRCM) and C57Bl/6 mice with transverse aortic constriction (TAC) as in vitro and in vivo models, respectively, to test the effects of XMU-MP-1 treatment. We used luciferase reporter assays, western blots and immunofluorescence assays in vitro, with echocardiography, qRT-PCR and immunohistochemical methods in vivo.

KEY RESULTS

XMU-MP-1 treatment significantly increased activity of the Hippo pathway effector yes-associated protein and inhibited phenylephrine-induced hypertrophy in NRCM. XMU-MP-1 improved cardiomyocyte survival and reduced apoptosis following oxidative stress. In vivo, mice 3 weeks after TAC, were treated with XMU-MP-1 (1 mg·kg-1 ) every alternate day for 10 further days. XMU-MP-1-treated mice showed better cardiac contractility than vehicle-treated mice. Cardiomyocyte cross-sectional size and expression of the hypertrophic marker, brain natriuretic peptide, were reduced in XMU-MP-1-treated mice. Improved heart function in XMU-MP-1-treated mice with TAC, was accompanied by fewer TUNEL positive cardiomyocytes and lower levels of fibrosis, suggesting inhibition of cardiomyocyte apoptosis and decreased fibrosis.

CONCLUSIONS AND IMPLICATIONS

The Hippo pathway inhibitor, XMU-MP-1, reduced cellular hypertrophy and improved survival in cultured cardiomyocytes and, in vivo, preserved cardiac function following pressure overload.

A novel 2-aminobenzimidazole-based compound Jzu 17 exhibits anti-angiogenesis effects by targeting VEGFR-2 signalling

BACKGROUND AND PURPOSE

Recent development in drug discovery have shown benzimidazole to be an important pharmacophore,. Benzimidazole derivatives exhibit broad-spectrum pharmacological properties including anti-microbial, anti-diabetic and anti-tumour activity. However, whether benzimidazole derivatives are effective in suppressing angiogenesis and its underlying mechanisms remain incompletely understood. In this study, we aim to characterize the anti-angiogenic mechanisms of a novel 2-aminobenzimidazole-based compound, Jzu 17, in an effort to develop novel angiogenesis inhibitor.

EXPERIMENTAL APPROACH

Effects of Jzu 17 on endothelial cell proliferation, migration, invasion, and activation of signalling molecules induced by VEGF-A, were analysed by immunoblotting, MTT, BrdU, migration, and invasion assays. We performed tube formation assay, aorta ring sprouting assay, matrigel plug assay, and a mouse model of metastasis to evaluate ex vivo and in vivo anti-angiogenic effects of Jzu 17.

KEY RESULTS

Jzu 17 inhibited VEGF-A-induced cell proliferation, migration, invasion, and endothelial tube formation of HUVECs. Jzu 17 suppressed VEGF-A-induced microvessel sprouting ex vivo and attenuated VEGF-A- or tumour cell-induced neovascularization in vivo. Jzu 17 also reduced B16F10 melanoma lung metastasis. In addition, Jzu 17 inhibited the phosphorylation of VEGFR-2 and its downstream signalling molecules in VEGF-A-stimulated HUVECs. Results from computer modelling further showed that Jzu 17 binds to VEGFR-2 with high affinity.

CONCLUSIONS AND IMPLICATIONS

Jzu 17 may inhibit endothelial remodelling and suppress angiogenesis through targeting VEGF-A-VEGFR-2 signalling. These results also suggest Jzu 17 as a potential lead compound and warrant the clinical development of similar agents in the treatment of cancer and angiogenesis-related diseases.

Mitochondrial protection by simvastatin against angiotensin II-mediated heart failure

BACKGROUND AND PURPOSE

Mitochondrial dysfunction plays a role in the progression of cardiovascular diseases including heart failure. 3-Hydroxy-3-methylglutaryl-CoA reductase inhibitors (statins), which inhibit ROS synthesis, show cardioprotective effects in chronic heart failure. However, the beneficial role of statins in mitochondrial protection in heart failure remains unclear.

EXPERIMENTAL APPROACH

Rats were treated with angiotensin II (1.5 mg·kg-1 ·day-1 ) or co-administered simvastatin (oral, 10 mg·kg-1 ) for 14 days; and then administration was stopped for the following 14 days. Cardiac structure/function was examined by wheat germ agglutinin staining and echocardiography. Mitochondrial morphology and the numbers of lipid droplets, lysosomes, autophagosomes, and mitophagosomes were determined by transmission electron microscopy. Human cardiomyocytes were stimulated, and intracellular ROS and mitochondrial membrane potential (ΔΨm ) changes were measured by flow cytometry and JC-1 staining, respectively. Autophagy and mitophagy-related and mitochondria-regulated apoptotic proteins were identified by immunohistochemistry and western blotting.

KEY RESULTS

Simvastatin significantly reduced ROS production and attenuated the disruption of ΔΨm . Simvastatin induced the accumulation of lipid droplets to provide energy for maintaining mitochondrial function, promoted autophagy and mitophagy, and inhibited mitochondria-mediated apoptosis. These findings suggest that mitochondrial protection mediated by simvastatin plays a therapeutic role in heart failure prevention by modulating antioxidant status and promoting energy supplies for autophagy and mitophagy to inhibit mitochondrial damage and cardiomyocyte apoptosis.

CONCLUSION AND IMPLICATIONS

Mitochondria play a key role in mediating heart failure progression. Simvastatin attenuated heart failure, induced by angiotensin II, via mitochondrial protection and might provide a new therapy to prevent heart failure.

Pharmacology of bisphosphonates in pain

The treatment of pain, in particular, chronic pain, remains a clinical challenge. This is particularly true for pain associated with severe or rare conditions, such as bone cancer pain, vulvodynia, or complex regional pain syndrome. Over the recent years, there is an increasing interest in the potential of bisphosphonates in the treatment of pain, although there are few papers describing antinociceptive and anti-hypersensitizing effects of bisphosphonates in various animal models of pain. There is also increasing evidence for clinical efficacy of bisphosphonates in chronic pain states, although the number of well-controlled studies is still limited. However, the mechanisms underlying the analgesic effects of bisphosphonates are still largely elusive. This review provides an overview of preclinical and clinical studies of bisphosphonates in pain and discusses various pharmacological mechanisms that have been postulated to explain their analgesic effects. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

Intranasal administration of a stapled relaxin-3 mimetic has anxiolytic- and antidepressant-like activity in rats

Background and Purpose

Depression and anxiety are common causes of disability, and innovative tools and potential pharmacological targets are actively sought for prevention and treatment. Therapeutic strategies targeting the relaxin‐3 peptide or its primary endogenous receptor, RXFP3, for the treatment of major depression and anxiety disorders have been limited by a lack of compounds with drug‐like properties. We proposed that a hydrocarbon‐stapled mimetic of relaxin‐3, when administered intranasally, might be uniquely applicable to the treatment of these disorders.

Experimental Approach

We designed a series of hydrocarbon‐stapled relaxin‐3 mimetics and identified the most potent compound using in vitro receptor binding and activation assays. Further, we assessed the effect of intranasal delivery of relaxin‐3 and the lead stapled mimetic in rat models of anxiety and depression.

Key Results

We developed an i,i+7 stapled relaxin‐3 mimetic that manifested a stabilized α‐helical structure, proteolytic resistance, and confirmed agonist activity in receptor binding and activation in vitro assays. The stapled peptide agonist enhanced food intake after intracerebral infusion in rats, confirming in vivo activity. We showed that intranasal delivery of the lead i,i+7 stapled peptide or relaxin‐3 had orexigenic effects in rats, indicating a potential clinically translatable route of delivery. Further, intranasal administration of the lead i,i+7 stapled peptide exerted anxiolytic and antidepressant‐like activity in anxiety‐ and depression‐related behaviour paradigms.

Conclusions and Implications

Our preclinical findings demonstrate that targeting the relaxin‐3/RXFP3 receptor system via intranasal delivery of an i,i+7 stapled relaxin‐3 mimetic may represent an effective treatment approach for depression, anxiety, and related neuropsychiatric disorders.

A novel and potent brain penetrant inhibitor of extracellular vesicle release

BACKGROUND AND PURPOSE

Extracellular vesicles (EVs) are constitutively shed from cells and released by various stimuli. Their protein and RNA cargo are modified by the stimulus, and in disease conditions can carry pathological cargo involved in disease progression. Neutral sphingomyelinase 2 (nSMase2) is a major regulator in at least one of several independent routes of EV biogenesis, and its inhibition is a promising new therapeutic approach for neurological disorders. Unfortunately, known inhibitors exhibit μM potency, poor physicochemical properties, and/or limited brain penetration. Here, we sought to identify a drug-like inhibitor of nSMase2.

EXPERIMENTAL APPROACH

We conducted a human nSMase2 high throughput screen (>365,000 compounds). Selected hits were optimized focusing on potency, selectivity, metabolic stability, pharmacokinetics, and ability to inhibit EV release in vitro and in vivo.

KEY RESULTS

We identified phenyl(R)-(1-(3-(3,4-dimethoxyphenyl)-2,6-dimethylimidazo[1,2-b]pyridazin-8-yl)pyrrolidin-3-yl)-carbamate (PDDC), a potent (pIC₅₀  = 6.57) and selective non-competitive inhibitor of nSMase2. PDDC was metabolically stable, with excellent oral bioavailability (%F = 88) and brain penetration (AUC_brain /AUC_plasma  = 0.60). PDDC dose-dependently (pEC₅₀  = 5.5) inhibited release of astrocyte-derived extracellular vesicles (ADEV). In an in vivo inflammatory brain injury model, PDDC robustly inhibited ADEV release and the associated peripheral immunological response. A closely related inactive PDDC analogue was ineffective.

CONCLUSION AND IMPLICATIONS

PDDC is a structurally novel, potent, orally available, and brain penetrant inhibitor of nSMase2. PDDC inhibited release of ADEVs in tissue culture and in vivo. PDDC is actively being tested in animal models of neurological disease and, along with closely related analogues, is being considered for clinical translation.

Incidence of direct oral anticoagulant use in patients with nonvalvular atrial fibrillation and characteristics of users in 6 European countries (2008-2015): A cross-national drug utilization study

Aims

To estimate the incidence of direct oral anticoagulant drug (DOAC) use in patients with nonvalvular atrial fibrillation and to describe user and treatment characteristics in 8 European healthcare databases representing 6 European countries.

Methods

Longitudinal drug utilization study from January 2008 to December 2015. A common protocol approach was applied. Annual period incidences and direct standardisation by age and sex were performed. Dose adjustment related to change in age and by renal function as well as concomitant use of potentially interacting drugs were assessed.

Results

A total of 186 405 new DOAC users (age ≥18 years) were identified. Standardized incidences varied from 1.93–2.60 and 0.11–8.71 users/10 000 (2011–2015) for dabigatran and rivaroxaban, respectively, and from 0.01–8.12 users/10 000 (2012–2015) for apixaban. In 2015, the DOAC incidence ranged from 9 to 28/10 000 inhabitants in SIDIAP (Spain) and DNR (Denmark) respectively. There were differences in population coverage among the databases. Only 1 database includes the total reference population (DNR) while others are considered a population representative sample (CPRD, BIFAP, SIDIAP, EGB, Mondriaan). They also varied in the type of drug data source (administrative, clinical). Dose adjustment ranged from 4.6% in BIFAP (Spain) to 15.6% in EGB (France). Concomitant use of interacting drugs varied between 16.4% (SIDIAP) and 70.5% (EGB). Cardiovascular comorbidities ranged from 25.4% in Mondriaan (The Netherlands) to 82.9% in AOK Nordwest (Germany).

Conclusion

Overall, apixaban and rivaroxaban increased its use during the study period while dabigatran decreased. There was variability in patient characteristics such as comorbidities, potentially interacting drugs and dose adjustment. (EMA/2015/27/PH).

Interactions of nanomaterials with ion channels and related mechanisms

The pharmacological potential of nanotechnology, especially in drug delivery and bioengineering, has developed rapidly in recent decades. Ion channels, which are easily targeted by external agents, such as nanomaterials (NMs) and synthetic drugs, due to their unique structures, have attracted increasing attention in the fields of nanotechnology and pharmacology for the treatment of ion channel-related diseases. NMs have significant effects on ion channels, and these effects are manifested in many ways, including changes in ion currents, kinetic characteristics and channel distribution. Subsequently, intracellular ion homeostasis, signalling pathways, and intracellular ion stores are affected, leading to the initiation of a range of biological processes. However, the effect of the interactions of NMs with ion channels is an interesting topic that remains obscure. In this review, we have summarized the recent research progress on the direct and indirect interactions between NMs and ion channels and discussed the related molecular mechanisms, which are crucial to the further development of ion channel-related nanotechnological applications.